(1) Field of the Invention
This invention relates to novel antibiotics of the pyrrolo (1,4) benzodiazepine family having both antibacterial and antitumor activity and to their production by fermentation of a new microorganism.
(2) Description of the Prior Art
The antitumor antibiotics of the present invention are new members of the anthramycin-sibiromycin group of antibiotics.
Among the members of this group are anthramycin having the formula ##STR1## which is disclosed in J. Am. Chem. Soc. 87: 5791-5793, (1965), mazethramycin having the formula ##STR2## which is disclosed in J. Antibiotics 33(6): 665-667, (1980), sibiromycin of the formula ##STR3## which is disclosed in J. Antibiotics 27(11): 866-873 (1974), and J. Antibiotics 25(11): 668-673 (1972), tomaymycin of the formula ##STR4## which is disclosed in J. Antibiotics 25: 437-444 (1972), neothramycins A and B of the formula
______________________________________ ##STR5## R.sub.1 R.sub.2 ______________________________________ neothramycin A H OH neothramycin B OH H ______________________________________
which are disclosed in J. Antibiotics 29(1): 93-96 (1976) and J. Antibiotics 30: 340-343 (1977), and chicamycin of the formula ##STR6## which is disclosed in J. Antibiotics 37: 191-199 (1984). BMY-28121 is the first example of this group which has only one substituent (9-methoxy) on the benzene ring. The absence of a hydroxy group on the ring is another unique structural characteristic of the antibiotic.